Hydraulic anchor tool



y 1, 1956 J. J. LANE 2,743,781

HYDRAULIC ANCHOR TOOL Filed Aug. 25, 1952 3 Sheets-Sheet l John J. L 008INVENTOR.

BY Z n A TTORNE Y y 1, 1956 J. J. LANE 2,743,781

HYDRAULIC ANCHOR TOOL Filed Aug. 25, 1952 5 Sheets-Sheet 2 /72 John J.Lane IN VEN TOR.

$2: I r I i Q E, Z. i Q a Z ZA ii A TTORNE Y May 1, 1956 J. J. LANEHYDRAULIC ANCHOR TOOL Filed Aug. 25, 1952 3 Sheets-Sheet 3 9/ g/zf I g wa C8 7 if w 4 23 (Q if 55:

e l a? r 4 59 & W

3 002 John J, Lane 90 INVENTOR.

gem M ATTORNEY HYDRAULIC ANCHOR T L John J. Lane, Dallas, Tex., assignorto The Guiberson Corporation, Dallas, Tex., a corporation of DelawareApplication August 25, 1952, Serial No. 306,227

11 Claims. (Cl. 166-212) This invention has to do with improvements in atry draulically operated anchor tool. It is introduced into asurrounding cylinder, until in proper position, whereupon it is thenfirmly anchored thereto by specially constructed teeth, which areradially mounted and slideably carried in its walls and arranged to beforced outwardly thereof and into penetrating engagement with the innerface of the cylinder. The anchoring operation is reversible, and thistool may be completely and easily released from such engagement, andthen withdrawn from the cylinder when desired.

This invention employs a barrel having a hollow interior; and a numberof separate and independently operated pistons are slideably carried bythe wall of the barrel, so as to be movable therethrough in response tofluid pressure introduced into the barrel behind the head of pressureintroduced into the barrel, until the free end of each piston isseparately and individually set in biting engagement with the inner wallof the surrounding vessel, to which the tool is thus securely butreleasably anchored.

The free end of each separate piston, extendable outside of the barrelof the tool, is provided with only a single tooth; and the outermost endof each such single tooth is provided with a biting or gripping edge forengagement in making anchor; and such edge is continuously kept sharpand capable of slight penetration into the walls of the surroundingvessel to which the tool is anchored. Each individual tooth is keptself-sharpened by the regular introduction, use and removal of the tool,in normal operation, within the surrounding vessel, pipe or casing towhich the tool is set and fastened in a releasable holding relation.

Each anchoring tooth of this device has behind it a single piston, whichis individually moved and operated, inwardly and outwardly, by fluidpressure. Such pressure is applied to the inner side of the piston toforce its single tooth into positive anchor engagement; and release fromengagement may be effected by the application of fluid pressure to theouter side of the piston.

Among the more important objects of this invention are the following: Anextremely compact, highly dependable, self-centering, hydraulic anchortool, wherein anchorage is provided by a multiple number of separatelyspaced teeth so constructed and arranged that each tooth is singlyoperated by remote control; and in which each tooth engages and doesfull duty and carries equal load; and in which each individual grippingtooth equally prevents tool movement in every direction; and in whichthe cited States Patent 0 ilfi lfifliil Patented May 1, 1956 "iceefiectiveness of hydraulic power is greatly increased, so that there isexerted extremely efifective unit power at the gripping point of eachtooth.

Other objects will become apparent in a reading of this specification.

The uses of the hydraulic anchor tool which is the subject of thisinvention are many, and they extend into the several fields ofindustrial activity. This tool is primarily made for use in wells, suchas wells for oil, gas and Water. However, it must be recognized that thetool is essentially an anchor. That is to say, the main purpose of thistool is to provide a holding device. It works to hold together twobodies, one of which is the anchor tool itself, and the other of whichis a surrounding vessel having an inner Wall spaced outwardly from andabout the barrel of this anchor tool.

The tool may be used in securing and holding together two such bodies,in an extremely strong, stable and rigid connection. Such connection maybe maintained for such period of time as may be desired, and it may beinstantly and easily released at Wil.

The capacity of the tool to be so completely, although releasahly, fixedwithin a surrounding vessel, as to prevent relative movementtherebetween, is but one of the advantages of its use. It may also beused to provide the unyielding holding, in any required position ofprecisely maintained relationship, of some other tool or deviceconnected to the anchor itself. Such other tools or devices. may beplaced at or near, or spaced apart from, one or the other end (or bothends) of the anchor tool itself, and attached thereto. Therefore, whenthe auchor tool is set in place, it maintains the fixed placement of anydevice fastened to it beyond either of its ends.

In various manufacturing and machine shop operations, this anchor toolmay be employed to rigidly and accurately hold any material or machineor structure or. casting which may be engaged or carried by this tool,so that operations (such as lifting, pressuring, cutting, forming,shaping, heating, cooling, and the like) may be car ried out with andupon the structure, material or thing so engaged or carried by thistool.

In the accompanying drawings typical and suitable forms of thisinvention and its operative mechanism are made clear. The drawingsdisclose the use of such typical apparatus to provide an anchor tool inan oil well.

In these drawings different parts of the structures are indicated bydifferent numerals; and where the same numeral identifies several parts,it is meant that these parts are the same.

The drawings set out preferred forms of two types of this invention. Thetype of hydraulic anchor tool which is identified, by the letter A, inthe drawings, discloses structure wherein relative rotative motion isnot permitted between the anchor barrel and the pipe string or rod orline which carries or supports it. On the other hand, the structureshown as at B, in the drawings, presents arrangement whereby a centralmandrel, which may be connected to a pipe string so as to become a partthereof, is capable of being rotated in the anchor barrel when thelatter is firmly anchored to any surrounding pipe.

Various modifications of the mandrel may be made, especially withrespect to provisions for fluid pressure ports and channels therethroughand/ or thereabout.

Modifications are also shown in design and arrangement of the sleevewhich may be employed in the nonrotatable type of anchor tool. Sleeves,of proper structure, are usually provided as a backstop for the separateand individually operated piston teeth, Where no other structure hasbeen arranged to limit the inward movement of each piston. Theindividual pistons themselves permit of a considerable range ofmodification, as is made evident by the drawings.

Preferred and modified forms of the hydraulic anchor tool are set forthin the drawings to illustrate both fundamental and variable parts andstructures which may be employed in this device. In the accompanyingdrawings:

Fig. I shows a partially sectionalized elevational view of a typicalhydraulic anchor tool, with pistons recessed.

Fig. II shows a section taken along line II-II of Fig. I.

Fig. III shows an exploded perspective view of a typical piston andpiston jacket.

Fig. IV shows a partially sectionalized elevational fragmentary view ofan anchor tool, with pistons extending and engaging the inner wall ofsurrounding pipe.

Fig. V shows a partially sectionalized elevational view of a modifiedform of piston.

Fig. VI shows a partially sectionalized elevational view of anothermodified form of piston.

Fig. VII shows a sectionalized elevational fragmentary view of part ofan anchor tool carrying a modified form of piston jacket and a modifiedform of sleeve or backstop.

Fig. VIII shows a partially sectionalized elevational view of a modifiedform of hydraulic anchor barrel having a rotatable mandrel extendingtherethrough; and in this view the anchor piston teeth (not shown) mustbe mounted in the passageways in the wall of the barrel, such view beingprimarily intended to show an arrangement for allowing relative rotationbetween a modified barrel and a modified mandrel.

Fig. IX is a fragmentary cross sectional elevational view showingmodified means for mounting a piston and jacket in the barrel.

Fig. X is a fragmentary cross sectional elevational view showing othermodified means for mounting a piston and jacket in the barrel.

The application and use of this anchor tool in various fields ofindustrial activity will become apparent when its use is made more clearin one particular field, such as in the operation and/or conditioning ofwells in the earth.

In oil well practice, it is customary to set conventional packers closeto the bottom of the well and produce oil through the tubing, or smallerpipe, which is carried within the well casing.

An important use of this anchor tool is found in normal production ofoil and gas from wells. It may be used in conjunction with an oil wellpump, which is attached to the lower part of the tubing string 21 andplaced within the casing 22 at a point below normal oil level therein.This tool is used to anchor the tubing to the casing, by being placedabove the pump in the tubing string. By making and maintaining suchanchor, the objectionable tube breathing or stretching is materiallyreduced. This results in greater efiiciency in each pump stroke of thepump operations.

The setting and operation of this hydraulic anchor tool is simple andeasy. It has few parts; and every part is quite durable and veryeffective in function.

Fluid pressure is introduced into tubing string 21 and flows intocentral conduit 18 of the anchor tool, and passes through pressurecommunicating ports 51 into the enlarged central bore 13 of anchorbarrel 11. Such pressure is exerted independently against each of thenumerous piston heads 41. This causes the outward movement of eachpiston body 39, until each individually moved piston tooth 40 isextended outwardly of barrel 11. Such extension will cause biting edge43 of each tooth to strike and slightly penetrate the wall of casing 22.Thereupon the tool is firmly anchored to the casing by the engagement ofthe many piston teeth which are slideably mounted in the wall of thebarrel of the tool.

Each tooth may be provided with a jacket 31, mounted in passageway 30,the latter being made by drilling a hole through the barrel wall. Jacket31 is provided with a flange 32, atits inner end, which prevents theejection of the jacket. The outer end of the jacket is provided with aniii-turned lip which affords retaining shoulder 33 to prevent ejectionof the piston by limiting its outward travel. The jacket is providedwith a resilient seal ring 37 carried in annular recess 36 made in theouter wall near its forward end. The enlarged piston head 41 is providedwith flexible piston ring 43 carried in an annular recess 42, which isprovided in the outer wall of the piston head. The jacket 31 providesenlarged guide surface 35 for guiding the piston head, and smaller guidesurface 34 for guiding the piston body 39. The outermost surface of body39 afiords load bearing surface 49 of the piston.

The tooth is provided with bevel 45, the forward end of which terminatesin biting edge 48. This biting edge may be kept narrow by the provisionof concavity 47 arranged in the extreme forward end of the tooth. Acylindrical sleeve 50, carried within the barrel 11 in slightly spacedrelation thereto (thus providing annular main pressure conduit 19),constitutes a backstop for all pistons and affords means whereby theirinward movement is limited.

This hydraulic anchor tool invention presents radical improvements indesign, construction and operation, in mold-purpose utility, in generaleffectiveness, in simplicity and ease of control in setting andreleasing, and in rugged strength, over prior art attaching andanchoring devices which have been heretofore operated either bymechanical or hydraulic means.

This hydraulic anchor (A or B) provides a barrel (11 or 88) within whichis found a pressure chamber (19 or 84). Radially extending through thewall of the barrel there is arranged a number of singly acting andsymmetrically spaced pistons (41 and modifications 59, 65, 76 and 99).Each such piston has an enlarged piston head at its inner end (typicalof which is shown as at 41), whereby hydraulic pressure from thepressure chamber may be applied thereagainst with great holding eiiect.

The free ends of these pistons are relatively small compared to thegreater piston head area; and pressure within the barrel will force thefree ends of the pistons to pop out of the barrel. They are made toextend radially in a symmetrical pattern revealing spaced individualteeth. One form of tooth is shown as'at 40. There is a single pistonbehind each tooth.

The free or contacting end of each tooth is conical or frusto-conical inshape. Only the beveled or conelike end of a tooth projects beyond theouter wall of the barrel of this tool, so that when pressure is releasedwithin the barrel the free and smaller and somewhat pointed ends of eachpiston tooth will immediately retreat entirely into the barrel wall, itit strikes any obstruction, going in or out of the hole. The resultthereof is that after pressure is relieved behind the piston heads, notooth which may remain extended beyond the body wall can hang up in thecasing. Instead of hanging up, the teeth are driven back into the barrelupon striking anything in the annulus of the well which would or couldcause the old style slips to bind or hang up or become wedged.Therefore, this hydraulic anchor tool will not stick in the hole. Thevery thing that would cause a conventional slip to get stuck repels thisimproved piston tooth, immediately obviating the possibility of a hangup. i

However, in normal operation, no once extended tooth of this anchor toolremains extended after pres sure is relieved in the barrel. Instead,each tooth retracts at once intothe barrel in much the same manner as aturtles head disappears within its shell in the presence is opened andits internal pressure relieved, and a greater pressure is allowed in theannulus.

Therefore, when this anchor tool is thus released from engagement withthe wall of a surrounding casing, the pistons retract inwardly of thebarrel in response to greater pressure outside of the barrel.

Normal wear tends to sharpen the teeth of this tool. They are rotatableand self-sharpening. They may be sharpened by engaging and disengaingthe wall of the casing, which action occurs in a tilting movement. Eachindividual tooth is allowed to tilt slightly in its piston jacket.(Numeral 31 shows a typical jacket.) This is permitted by a slightlooseness around the piston tooth, together with a resilient seal ring43 about the piston. This tilt is caused by the transferring of thepressure thrust, exerted against the tool, to the wall of the casing inwhich the several teeth find their respective engagements. By this ismeant that one gripping or digging edge of a rotatable piston toothslightly penetrates the Wall of the casing to a greater. extent than there maining edges of the free or toothed end of the piston.

Construction which permits rotation in the teeth therefore allows atilted tooth to be sharpened on one. edge only at one time and onanother edge at another time. Friction and abrasion during engagementand during the momentary release of the tooth and'during the trip of thetool into and out of the well, all combine to sharpen a cutting edge onthe tooth, first on one side and then on another. Such cutting edges areshown as at 48, 63 and 66.

The pistons of this tool are quickly and inexpensively produced byautomatic screw machines. This allows them to be made round, and thuspermit their rotation within a round jacket 31, which is' provided forthem to slide in. The jacket itself, also being round, is capable ofbeing made at low cost on automatic screw machines. Such possibility foreconomy in manufacture reduces labor and saves time. This in itself is avaluable advance in the art of producing slip engaging means usable intoothed anchoring devices.

These cheaply produced piston teeth may be inexpensively replaced whentheir engaging ends become worn off too short to make their continueduse practicable. Since no other part of this tool experiences any wearor abrasion of consequence, it is of great value to be able toinexpensively replace worn teeth. Therefore, this tool has an uncommonlylong life. The operation of replacing the piston teeth is very simple. Anew toothed piston element may be quickly inserted in the barrel, as ismade plain in the drawings. SeeFigs. l, II, III, IX and X. It may beinserted from within the ba.rrel or from the outside of" the barrel,depending on the type of jacket and piston employed. :Forms of thejacket are shown as at 31, 70, 91 and 95.

The stepped-down design of the entire piston element results in greatimprovement in the (stability of the piston in its sliding movement, andprevents binding of the piston as it slips back into the wall of thebarrel. This novel design for individual piston elements presentscertain advantages, including these: i

(a) Every point on the piston is symmetrical about the center line ofthe piston; and this makes the piston nondirectional, and l (b) Thefluid drive area (piston head area, typically shown as at 41) is alwaysmuch greaterthan the gripping area (48, 63, 66) of the free, engagingtooth end of the piston, and r V (c) The fluid drive diameter of thepiston (shown as at 41) is greater than the bearing diameter (shown asat ill), which latter diameter is along the mid-part of the piston; and

(d) The load bearing diameter of the piston is greater than the diameterof the toothed end of the piston.

These four elements of design are preferably kept in the making or"pistons for this anchortool. However, the

greatest advantage of such design is found in the provision of a fluidpressure area (piston head area) far in excess of the area of the free,gripping end of the piston which provides its engaging tooth. Suchdesign insures the actual (although slight) penetration of an edge orpoint of a tooth into the casing wall, in response to the relativelygreat fluid pressure applied to the exceedingly larger area of thepiston head. Such diiference in the ratio of these two most importantareas is of primary importance in the construction of the piston toothfor this anchor tool. It is recommended that this difference in ratio beat least three to one; and it is to be noted that an increase ofdifference in the ratio (which may be achieved by making the biting endof the tooth of less area by being pointed) will result in the anchortool having greater penetration. By varying the size of penetrating ofthe tooth, the holding characteristics may be varied, in contemplationof load carried, nature of contacting metals and the measure ofhydraulic power employed.

Such difference between the area to which fluid pressure is applied andthe area of engagement with the casing wall is not encountered inconventional hydraulically operated apparatus used for anchoringpurposes in oil field operations. In fact, such prior art devices arenot found to use a single tooth individually and separately moved toengagement by hydraulic force.

It is to be noted that whatever the variations employed in the design,and making of this anchor tool, and however the individual pistons maybe designed, and however they. may be mounted and slideably carried inthe wall of the barrel of the tool, it is apparent that throughout thevarious modifications (as shown in the drawings or as may be otherwisemade) there is always provided a single piston under each tooth. Aseparate piston powers each tooth quite independently of every othertooth, and this results in very high engagement efficiency in each toothof the tool.

With such design and construction as is presented by this invention formaking and using individually moved and operated teeth, it is nowpossible to accurately calculate the force required to maintain completeengagement of a tooth against any known thrust; and such calculation canbe made at any given hydraulic pressure. This is so because the basicfactors affecting each individual tooth can now be known through the useof a piston tooth designed as here presented. Given a certain sidethrust against the tooth in engagement, then the other factors are thepressure on a piston head of certain area and the further factor of theengaging area of the free end of the tooth. No longer is it necessary totake into consideration the weight of the tubing or any part of thetubing weight whatsoever, as in the conventional practice in olderdevices. With this tool it is possible to hold any portion of anypressure load designed.

In this connection it is to be noted that the barrel of the tool may bemade as long or as short as the requirements of a given job and load tobe carried may indicate.

The total number of toothed pistons carried by and operated from thebarrel may be varied, as needed. For instance, only one horizontal bandof pistons may be used, as by employing only the pistons shown in Fig.11. Fewer pistons may be used in a tool having only one band of pistonsthan is shown in Fig. 11; and more pistons may be used than shown insuch figure.

Tools having many bands of pistons may be employed. Tools may be madewith no two pistons in the same horizontal band. Tools employing theinvention here presented havebeen made carrying anywhere from three toninety-six pistons.

In mounting the anchor tool in tubing string, adapter 20 is arrangedbetween barrel cap 15 and end of tubing 21, and these members areprovided with suitable connecting means. Bore 14 in the barrel cap hasbeen threaded for connection. However, any suitable connection means maybe employed. At the inner end of bore 14 the enlarged main pressureconduit 19 begins. This allows the provision of sleeve retainingshoulder 16, to prevent upward movement of sleeve 50. Barrel cap 15should be provided with beveled outer surface 17; and the lower end ofbarrel 11 should be beveled as at 25. Such provisions facilitate theintroduction and withdrawal of the tool from a pipe.

Sub 23 may be employed as a connector between the anchor body and tubingor other pipe, or to connect the anchor body with a packer or othertool.' This sub is threaded at each end, but any suitable connectionmeans may be employed. It is to be noted that sub 23 retains one end ofsleeve 50. This sub should be beveled on its outer wall as at 24.

Fig. VII shows modified piston jacket 70, mounted in modified passage25, the outer ends of both members being beveled to form a weldingrecess 74, which may be sealed with fused metal, as at 75, thus securingthis particular type of jacket in the barrel wall so that it is notreadily removable therefrom. Such construction makes unnecessary anyflange on the jacket to restrain it from outward movement. This jacketis provided with retaining lug and piston guide 72 which affordsretaining shoulder 73 to limit the outward movement of piston 76.

Any desired sleeve of suitable varied form may be employed as means tolimit the inward movement of pistons. For instance, instead of standardsleeve 50, sleeve 77 may be used, and such sleeve is to be provided withfluid pressure ports 78 therethrough.

Instead of the usual flexible piston ring 43, modified piston packingring 64 may be employed with any piston head. Instead of a piston toothsuch as standard Fig. IV, modified piston tooth 60 may be employed toafiord a tooth having a flat end 61 and a different bevel 62.

Another modified piston 65 is shown in Fig. V1, with a tooth coming to apoint, as at 66, and having modified bevel 67.

Other forms of construction in piston teeth are shown, as the bevel 45,on piston 41, such bevel terminating in a free end having a concavity 47to provide a circular biting edge, as shown at 48.

The most fundamental change or modification indicated herein, over theusual or preferred embodiment A of this tool (Figs. I, II and III) isdisclosed by the tool B, shown in Fig. Vill, wherein barrel or body 88is arranged and constructed for relative rotative motion with respect tomandrel 80. This mandrel is firmly secured to coupling 90, the latterbeing attached through the use of threads 82.

Central conduit 83 of mandrel 80 is free and unobstructed, andcommunicates freely with tubing 21.

Fluid pressure ports 81 are provided through the wall of mandrel 80 tocommunicate with main pressure conduit 84 of barrel 88. This latterconduit allows fluid pressure to be exerted upon pistons carriedinpassageways 85, which. are arranged through the wall at spacedintervals.

An annular recess 86 is provided at each end of barrel 88 to receive aresilient sealing ring 87. Each end of the barrel in this tool should bebeveled, as at 89.

Through the use of modified tool B, firm anchor may be made of barrel 88with surrounding casing wall 22, yet the tubing string 21 may berotated, and the mandrel 80, firmly attached thereto, will rotate inbarrel 88. There are many occasions upon which it is necessary to rotatethe tubing. It may be necessary to make rotary movements to lock andunlock the tubing from a packer or other tools; and at the same time itmay be very necessary that the anchorage of this tool be understood.Such is easily practiced with the use of hydraulic anchor tool B.'-Figures IX and X show modifications allowing both jacket and piston tobe inserted in the Wall of barrel (11 or 88) from the outside of thebarrel.

In Fig. IX jacket 91 is set into modified passageway 92, which isprovided 'withpiston retaining shoulder 93;.

Jacketretaining screw 94 is set into the outer face of the wall, in suchway as to hold in place modified jacket 91. InFig. X modified andexterior threaded piston jacket 95 is inserted in the wall from theoutside, by being placed in modified passage 96, which is provided withthreads complementary to those on the jacket. This passage is providedwith piston retaining shoulder 97 to limit the inward movement of anypiston carried by the jacket. This particular jacket 95 should beprovided with wrench holes 98 to receive a wrench for inserting andwithdrawing the threaded jacket from the wall.

The central conduit (18 or 83) of both anchor tools A & B will allow thepassage therethrough of any tool or apparatus which may be passedthrough the tubing connected with the tool. If it is desired to cleanthe main pressure conduits 19 or 84, it is only necessary to pass-a swabthrough the anchor tool. This will cause fluid to circulate back to thesleeve or mandrel and thus clean out all channels in the tool.

Although it is not shown in the drawings, a plug or cap may be used toclose one end of the barrel of this tool. With a pipe connected to theother end of the tool, fluid pressure may be introduced to test thetool, both at the factory and in the field. Such a plug may be employedwhere it is desired to set this anchor within any cylindrical vessel.

I claim:

1. In a tool for anchoring pipe in a well, a hydraulic anchor toothcomprising: a cylindrical body; an annular shoulder on one end of thebody; a beveled tooth portion on the other end of the body, said toothportion being concave at its outer end.

2. In a hydraulic anchor, an elongate tubular barrel; a plurality oflateralpassages provided through the wall of the barrel and arranged inspaced relation; a piston jacket slideably mounted in each such passage;a piston slideably carried in each such jacket, said pistons being soconstructed as to prevent the flow of fluid therethrough; means to limitthe outward movement of the jackets in the passages; sealing meanscarried about each jacket arranged to seal between the jackets and thepassages for preventing fluid from passing through the barrel wall; anda tubular piston stop arranged within the barrel to limitthe rearwardmovement of each piston.

3. In a hydraulic anchor, an elongate tubular body; a plurality oflateral passages provided through the wall of said body and arranged inspaced relation; a piston jacket slideably mounted in each such lateralpassage, each such jacket having an out-turned flange at its inner endengageable with the inner wall of the body to limit outward movement ofthe jacket in the passage, and each such jacket being open at each end;an in-turned shoulder in each such jacket intermediate the end thereof;a piston slideably carried in each jacket, the inner end of each suchpiston being provided with an enlarged p ston head engageable with thein-turned shoulder to limit outward movement of the piston in thejacket; and a piston stop carried within the body behind the pistonsengageable with the pistons to limit inward movement of the pistons withrespect to the body.

4. In a hydraulic anchor, an elongate tubular body; a plurality oflateral passages provided through the wall of the body and arranged inspaced relation; a piston acket slideably and rotatably mounted in eachsuch passage, each such jacket having an in-turned shoulder intermediateits ends; means to limit the inward movement of the jackets relative tothe tubular body; means to limit the outward movement of the jacketsrelative to the tubular body; a piston slideably and rotatably carriedin each such jacket, eachsuch piston being provided with an enlargedpiston head; and such pistons being so constructed as to prevent theflow of fluid therethrough.

5. In a-hydraulic anchor, an elongate tubular body; a plurality oflateral passages provided through the wall of said body and arranged inspaced relation; a piston jacket mounted in each such passage, each suchjacket having an in-turned shoulder intermediate its ends; a pistonslideably carried in each such jacket, the inner end of the piston beingprovided with a laterally extending flange, engageable with the shoulderto limit outward movement of the piston, and the outer end of the pistonbeing reduced to provide a tapered tooth, having a circular biting edge;each such piston being arranged to tilt in its respective jacket, andeach such piston being so constructed as to prevent the flow of fluidtherethrough.

6. In a hydraulic anchor, an elongate tubular barrel; a plurality oflateral passages provided through the wall of said barrel and arrangedin spaced relation; a piston jacket mounted in each such passage, thejacket having an in-turned shoulder intermediate its ends; a pistontooth slideably carried in each such jacket, the inner end of the pistontooth having an enlarged piston head provided thereon engageable withthe shoulder to limit outward movement of the piston tooth, and thepiston tooth being concave at its outer end; each such piston head beingsmaller in diameter than the inner diameter of its jacket, whereby theteeth may tilt in the jackets; and a resilient seal positioned about thepiston head arranged to seal between the piston head and the jacket.

7. In an anchor tool, a cylindrical tubular barrel having passagesthrough the wall thereof; a tubular jacket mounted in each passage; aninternal annular shoulder in each jacket; a cylindrical piston slideablycarried in each jacket, the outer end of the piston being beveled toterminate in a tooth of less diameter; an enlarged head on the toothengageable with the internal shoulder in the jacket to limit the outwardmovement of each piston; a sleeve carried in said barrel in spacedrelationship to the barrel and forming a stop to limit the inwardmovement of the pistons; and fluid communication passages through thewall of the sleeve.

8. In an anchor tool, a cylindrical body; at least one opening in thewall of said body; a sleeve slideably carried in the opening, saidsleeve being open at both ends; means to limit the inward movement ofthe sleeve relative to the cylindrical body; means to limit the outwardmovement of the sleeve relative to the cylindrical body; a piston toothslideably carried in the sleeve; means to limit the outward movement ofthe piston in the sleeve relative to the cylindrical body; and means tolimit the inward movement of the piston in the sleeve relative to thecylindrical body.

9. In an anchor tool, a cylindrical body; at least one opening in thewall of said body; a sleeve slideably carried in the opening, saidsleeve being open at both ends; means to limit the inward movement ofthe sleeve relative to the cylindrical body; means to limit the outwardmovement of the sleeve relative to the cylindrical body; a piston toothslideably carried in the sleeve; means to limit the outward movement ofthe piston in the sleeve relative to the cylindrical body; means tolimit the inward movement of the piston in the sleeve relative to thecylindrical body; packing means between the sleeve and the opening; andpacking means between the piston and the sleeve.

10. An anchor tooth assembly comprising: a sleeve having an outwardlyturned flange providing a shoulder at one end thereof; an annularshoulder turned inwardly of the sleeve; a piston tooth slideably carriedin the sleeve; said tooth having a beveled end, and an. annular flangeon the other end engageable with the inner shoulder of the sleeve;packing means disposed about the annular flange and arranged to sealbetween the piston and the sleeve as the piston slides therein; andpacking means carried in the outer wall of the sleeve, said last namedpacking means being arranged to seal between the sleeve and a passage inthe wall of a tubular body as the sleeve slides in the passage.

11. in an anchor tool, a cylindrical tubular mandrel; ports arrangedthrough the mandrel wall intermediate its ends; a cylindrical barrelrotatably carried around the mandrel, said ports being located withinthe cylindrical barrel; passages provided through the wall of thebarrel; packing means between the ends of the barrel and the outer faceof the mandrel wall; a cylindrical jacket mounted in each passage, saidjacket being open at each end, and having an internal annular shouldertherein; a cylindrical piston slideably carried in each jacket, theouter end of the piston being beveled to terminate in a tooth of lessdiameter; and an enlarged head on the tooth engageable with the internalshoulder in the jacket to limit the outward movement of each piston.

References Cited in the file of this patent UNITED STATES PATENTS1,188,001 May June 20, 1916 1,388,490 Suman Aug. 23, 1921 2,034,768ONeill Mar. 24, 1936 2,159,640 Strom May 23, 1939 2,302,567 ONeill Nov.17, 1942 2,352,700 Ferris July 4, 1944 2,381,929 Schlumberger Aug. 14,1945 2,582,719 Ramsey Jan. 15, 1952 2,603,292 Page July 15, 1952

